<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
  .box{
    width:800px;
    height:300px;
    background-color: #f00;
    position:relative;
  }
  .container{
    height:100px;
    background-color: #0f0;
    width:200px;
    margin:0 auto;
    position:absolute;
    right:0;
    left:0;
    width:200px;
    margin: auto;
    bottom:0;
    top:0;
  }
  
  </style>
</head>
<body>
  <div class="box">
    <div class="container">
    </div>
  </div>
</body>
</html>